1. Field of the Invention
The invention relates to an electrode thin film to be used in an all-solid lithium battery.
2. Description of Related Art
With a rapid proliferation of information-related equipment and communication equipment, such as personal computers, camcorders, and cellular phones, in recent years, it becomes important to develop a battery used as a power source of the information-related equipment or the communication equipment. In addition, in automobile industry, or the like, development of a high-power and high-capacity battery for electric vehicles or hybrid vehicles has been proceeding. Currently, among various types of batteries, lithium batteries becomes a focus of attention in terms of high energy density.
Currently commercially available lithium batteries employ an electrolytic solution that contains a flammable organic solvent. Therefore, it is necessary to install a safety device that suppresses an increase in temperature in the event of a short circuit or improve a structure or a material for short-circuit prevention. In contrast to this, all-solid lithium batteries that replace an electrolytic solution with a solid electrolyte layer do not use a flammable organic solvent in the batteries. For this reason, it is considered that the safety devices for the all-solid lithium batteries are simplified and the all-solid lithium batteries are excellent in manufacturing cost and productivity.
On the other hand, there is known a method of forming an electrode used in an all-solid lithium battery by aerosol deposition. For example, Japanese Patent Application Publication No. 2009-293107 (JP-A-2009-293107) describes that aerosol deposition (the pressure in the chamber is 100 Pa) is used to form a second film that contains lithium cobaltate (LiCoO2) and a phosphate solid electrolyte (Li1.3Al0.3Ti0.7(PO4)3) in a mixed state. On the other hand, Japanese Patent Application Publication No. 2008-166142 (JP-A-2008-166142) describes a method of forming an active material layer (electrode) by aerosol deposition although it is the method of forming an electrode for not an all-solid lithium battery but a lithium battery that uses an electrolytic solution.
In terms of increasing the power of a battery, an electrode thin film (active material layer) having a high lithium ion conductivity is sought.